Embodiments of the inventive concepts relate to stockers for stocking and transferring wafers and wafer shipping boxes in semiconductor fabrication lines, and methods of transferring the wafers and wafer shipping boxes using the stockers.
Semiconductor fabrication lines have been developed to transfer wafers and wafer shipping boxes using automatic transfer systems, and may employ a full-automatic transfer system in the long run. Both a front open shipping box (FOSB) and a front open unified pod (FOUP) have been used as transfer systems. The FOSB may not be automatically recognized in a transfer apparatus and may not be compatible with various transfer systems. Thus, the FOSB may be transferred/loaded to a dedicated transfer system by users, which may lower productivity. Also, in some existing automated transfer systems, an overhead hoist transport (OHT) configured to move a wafer shipping box upward/downward using a hoist and an overhead shuttle (OHS) configured to cause a wafer shipping box to slide in a horizontal direction can be used independently from each other.
In some existing transfer systems, wafers or a wafer shipping box may be loaded in the OHT/OHS, a stocker, and a rail-guided vehicle (RGV) in different directions, which may increase transfer time. Also, in some existing transfer systems, a wafer shipping box may be transferred in a state in which the door thereof is open and is thus may be vulnerable to pollution.